Environmental Occurrence Research Articles

Lateral Distribution, Environmental Occurrence and Assessment of Organic Pollutants in Surface Sediments of the West and South Peninsular Malaysia

Lateral Distribution, Environmental Occurrence and Assessment of Organic Pollutants in Surface Sediments of the West and South Peninsular Malaysia

Source-Supported Suspect Screening (4S) of Phytotoxins in Terrestrial and Aquatic Environments: A Field Study of Lupinus angustifolius L. (Blue Lupin).

Phytotoxins (PTs) are bioactive secondary metabolites produced by plants. More recently, they have been recognized as important aquatic micropollutants. Despite that, only a few PTs have been detected and reported in terrestrial and aquatic environments, while their source and leaching pathways remain largely unclear. Herein, we established a novel approach named source-supported suspect screening (4S) to discover PTs in different environments, investigate their environmental occurrences, identify their sources, and initiate discussions on their leaching mechanisms. The 4S-approach was demonstrated on a five-month Lupinus angustifolius L. (L. angustifolius) crop field experiment, where plant, topsoil, drainage water, and surface water were sampled and analyzed. As a result, 72 PTs (flavonoids and alkaloids) were identified at high confidence, with 10 PTs fully confirmed. Fifty-three PTs detected in soil or water were linked to L. angustifolius, among which 26 PTs were coherently detected in all three environmental compartments. The occurrence and abundance of PTs in terrestrial soil and aquatic environments were influenced by the plant growth stage and precipitation. Soil served as an intermedium when PTs leached from L. angustifolius to the drainage water, while the degree of retardation and eventual occurrence in the aquatic environment depended on both PTs and soil physico-chemical properties.

Occurrence, spatiotemporal variation, and ecological risks of organophosphate esters in the water and sediment of the middle and lower streams of the Yellow River and its important tributaries

Research on the environmental occurrence and behavior of organophosphate esters (OPEs) is very imperative. In this study, 12 targeted OPEs in the water and sediment samples collected from the middle and lower streams of the Yellow River (YR) and its tributaries during the dry, normal, and wet season were analyzed, to reveal their concentration, spatiotemporal variations, and ecological risks. The results indicated that the total concentration of OPEs (ΣOPE) ranged from 97.66 to 2433.30ng/L in water, and from 47.33 to 234.08ng/g in sediment. Tris(2-chloroethyl) phosphate (TCEP), tris(2-chloroisopropyl)phosphate (TCIPP), and triethyl phosphate (TEP) were the most abundant OPEs in the surface water and sediment. The OPEs levels in river water were ranked as the order of dry >normal >wet season. The ΣOPE concentrations in water and sediment were relatively high in the central and lower sections of the YR. The resorcinol-bis(diphenyl)phosphate (RDP) effectively transferred from the overlying water to the sediment. TCEP and RDP posed relatively higher ecological risk than other OPEs. Municipal and chemical industrial discharge might be sources of OPEs in the middle and lower streams of the YR.

ANALYSIS OF TEACHER DISCRIMINATION AGAINST STUDENTS OF SOCIAL STUDIES DEPARTMENT IN CENTRAL KALIMANTAN

The program carried out in SMA (Junior High School) is an effort to develop students' abilities. However, in its implementation, majors in Junior High School actually cause discriminatory actions against students majoring in social studies (Social Sciences) so that negative labels or stamps appear on students who take the major, both in the school environment and in the community. This study was conducted to find out :1). Causes of discriminatory occurrence in the school environment, 2). Impact on negative stamps/labels of the school environment. The method used is a qualitative method with a direct interview study type in the field. By seeking information from three (3) subjects/speakers, including two students and a permanent teaching teacher there at the high school. The negative label given to students majoring in social studies does not just happen, but there is a cause. The social sanctions given by the school environment stem from the attitudes and behaviors of children majoring in social studies that are not good, and tend to deviate from school rules or regulations.

Occurrence, spatial distributions, and temporal trends of bisphenol analogues in an E-waste dismantling area: Implications for risk assessment

The environmental occurrences of bisphenol analogues (BPs) have been extensively reported, whereas their concentration profile, spatial distribution, and temporal trend in e-waste dismantling area are still poorly understood. Herein, typical BPs (BPA, BPS, TBBPA, TBBPA-DHEE, and TBBPA-MHEE) were investigated in water, soil, and biological samples from three representative regions (FJT, JJP, and RIB) in e-waste recycling area in Taizhou, Zhejiang Province. Overall, the detection frequency of BPs in all samples was 100 %, confirming widespread presence of BPs in e-waste recycling area. Wherein, BPA was the predominant BPs in water (33.3 %) and soil samples (34.9 %), but TBBPA accounted for the largest proportion (41.3 %) in biological samples. In addition, the concentration of BPs in FJT was lower than that in JJP and RIB owing to the renovations on FJT by the local government in recent years, whereas the higher BPs level in RIB implied that elevated BPs contents was related to massive e-waste dismantling activities. From 2017 to 2021, a decreased trend of BPs concentration was observed in FJT, but aggravation of BPs levels in RIB was caused by the ongoing e-waste dismantling. The risk assessment revealed that the BPs in e-waste recycling area posed a low ecological and human health risk. Our finding could provide a valuable reference for the development of strict legislation systems related to e-waste management in China.

Spatial distribution of Dechlorane Plus and dechlorane related compounds in European background air

The highly chlorinated chemical Dechlorane Plus (DP) was introduced as a replacement flame retardant for Mirex, which is banned through the Stockholm Convention (SC) for its toxicity (T), environmental persistence (P), potential for bioaccumulation (B) and long-range environmental transport potential (LRETP). Currently, Dechlorane Plus is under consideration for listing under the Stockholm Convention and by the European Chemical Agency as it is suspected to also have potential for P, B, T and LRET. Knowledge of atmospheric concentrations of chemicals in background regions is vital to understand their persistence and long-range atmospheric transport but such knowledge is still limited for Dechlorane Plus. Also, knowledge on environmental occurrence of the less described Dechlorane Related Compounds (DRCs), with similar properties and uses as Dechlorane Plus, is limited. Hence, the main objective of this study was to carry out a spatial mapping of atmospheric concentrations of Dechlorane Plus and Dechlorane Related Compounds at background sites in Europe. Polyurethane foam passive air samplers were deployed at 99 sites across 33 European countries for 3 months in summer 2016 and analyzed for dechloranes. The study showed that syn- and anti-DP are present across the European continent (<MDL-2.6 pg/m3 and <MDL-12.3 pg/m3, respectively), including parts of the Arctic. This supports that these compounds have potential for long-range atmospheric transport to remote regions. The highest concentrations of Dechlorane Plus were observed in central continental Europe, with anti-DP fractions close to the commercial mixture of Dechlorane Plus. The only detected Dechlorane Related Compounds was Dechlorane-602, which was found in 27% of the samples (<MDL-0.33 pg/m3). The measured concentrations and spatial patterns of Dechlorane Plus and Dechlorane-602 in air across Europe indicate the influence of primary sources of these compounds on background concentrations in European air. Future air monitoring efforts targeting dechloranes is needed in both background and source areas, including consistent temporal trends.

Review of 6PPD-quinone environmental occurrence, fate, and toxicity in stormwater

The antioxidant N-(1,3-dimethylbutyl)-N?-phenyl-p-phenylenediamine (6PPD) is widely used to improve the durability of rubber. However, one of its transformation products, 6PPD-quinone (6PPD-Q), was recently found to be toxic. Herein, we aim to provide a comprehensive understanding of 6PPD-Q ecological and human-linked toxicity to facilitate the preparation of robust and specific environmental standards and policies. We reviewed 6PPD-Q environmental occurrence, fate, and toxicity originating from stormwater runoff and summarised its origin and environmental shaping conditions. Stormwater runoff was found to be the main driver in introducing 6PPD-Q into the environment. 6PPD-Q detection in roadside soils and other vehicle-related environments indicates that vehicle tyres are the major source of this compound; its presence in the soil can contaminate plants, thereby entering the food cycle. 6PPD-Q air concentrations were higher at roadside sites than at secluded building sites. Nevertheless, the mechanisms underlying 6PPD-Q toxicity and their relationship to various environmental factors, other contaminants, and removal technologies remain unknown. Addressing these gaps can help raise 6PPD-Q environmental risk awareness and facilitate development innovations to mitigate 6PPD-Q-linked risks.

COMPOSTOS PERFLUORADOS: UMA AMEAÇA AO OCEANO LIMPO

PERFLUORINATED COMPOUNDS: A THREAT TO THE CLEAN OCEAN. Per- and polyfluorinated compounds (PFAS) have been produced for more than seven decades and widely used in the most diverse areas, from food packaging, textile industry, aqueous film-forming foam to pesticides and surfactants. However, the characteristics that allow the wide range of applications also bring environmental concerns due to their persistence and toxic effects. Although the ocean might be the final destination of PFAS, in Brazil few studies have been carried out about PFAS and there are many gaps regarding their environmental occurrence, sources and distribution. Therefore, this article presents a review of the production, use, behavior in the environment, legislation, the occurrence of classic PFAS in the Brazilian marine environment, as well as perceptions about their fluorinated substitutes.

The reliability of evaporation ponds as a final basin for industrial effluent: Demonstration of an environmental risk management methodology

Recognizing and assessing environmental risk are key components of every industry management strategy. Projects need to make sure that a detailed environmental risk management strategy is applied by methodically recognizing and addressing threats from internal and external influences to comply with regulatory standards for environmental preservation and safeguarding. This study's goal is to use a novel technique to assess the impact of environmental risks related to the use of evaporation ponds as final basins for industrial effluents. It employs qualitative and statistical methodologies to identify areas where engineering and managerial safeguards' structure, functioning, and lines of defense have flaws that might result in an ecologically hazardous occurrence. Additionally, it will offer a risk evaluation based on the gravity of the impact and the likelihood that the environmental occurrence would happen by using evaporation ponds to store industrial effluents. While the environmental threat would be entirely removed, it must be capable of reducing it to ALARP. The environmental risk assessment matrix will serve as a key factor in determining whether the environmental risk level linked with an evaporation pond is acceptable, as determined by the likelihood and impacts. The result of this research allows industrial units to recognize and control potential environmental risks associated with effluents by practically implementing a new environmental risk matrix based on several environmental and ecological effects with probability factors.•This study aims to assist industrial operators, especially power plants, manage environmental risk by combining ALARP concepts with other factors to evaluate risk acceptance and tolerance levels.•The Physico-chemical characteristics of effluent collected in the evaporation pond reveal that evaporation has a deleterious impact on such industrial effluent, as evidenced by a large increase in various effluent properties, some of which exceed the limit values.•A risk evaluation found that effluent collected in the evaporation pond has a detrimental negative impact on industrial effluents. This was evidenced by a significant rise in associated activities. This could increase the expense of operating and managing evaporation ponds, which could harm the ecosystem.

НОВЫЕ МЕТОДИЧЕСКИЕ ПОДХОДЫ В ВОПРОСАХ ИЗУЧЕНИЯ РАЗВИТИЯ СИНДРОМА ЭМОЦИОНАЛЬНОГО ВЫГОРАНИЯ У СТУДЕНТОВ ВУЗОВ

The article is devoted to the study of the development of the syndrome of emotional burnout among students of a technical university. The content of the concept of "burnout syndrome" is revealed, a theoretical analysis of this phenomenon is carried out, and the reasons for its occurrence in the student environment are analyzed. The paper shows that negative factors in the form of suboptimal learning conditions that take place in the organization of the educational process have a detrimental effect on mental health, cause a decrease in the level of stress resistance in students, which causes them to develop a burnout syndrome. The authors studied the dependence of the development of the emotional state syndrome on the psychological profile of students. It is proposed, depending on the results obtained during testing on the 16PF multifactorial personality questionnaire, to attribute students to the "negative" or "positive" pole. On the basis of the test results obtained and the correlation analysis carried out, "psychological portraits" of students of the Institute of Engines and Power Plants of the Samara National Research University named after Academician S.P. Queen, who have a tendency or, conversely, resistance to the development of burnout syndrome. In order to prevent the development of the phenomenon of emotional burnout, ways and methods for identifying early signs and preventing its development in students are proposed.

Geology of the Copper Mineralization in Proterozoic Ajabgarh Meta-Sediments of, Dokan-Dariba Belt, Sikar District Rajasthan Northwestern India

The Khetri copper belt is a well-known metallotect in northern part of Delhi fold belt in Rajasthan. On the eastern margin of the Khetri sub basin of North Delhi basin separated by a basement high, another sub basin Alwar-Ajabgarh sub basin exposes that a thick sequence of Ajabgarh group of rocks overlies a thick arenaceous sequence of Alwar group of Delhi Super Group of rocks. The Ajabgarh meta sediments here in the Neem Ka thana area are characterized by presence of Bornite dominated copper mineralization with silver association and minor presence of Pb. The mineralization has been described by various workers as strata-bound, hypogene and IOCG. But these inferences are based on part information and the inference drawn is sectorial in nature. The current study includes a holistic study based on exploration over a period of more than two decades and the data generated suggest thereof, that this syngenetic sulphide mineralization associated with the sedimentation of marl and carbonate rocks. Subsequently it has been relocated during 2nd deformation accompanied by epigenetic component of mineralization depicted in terms of vein filled coarse grained aggregates of bornite and chalcopyrite disposed across the general disposition of litho-package. The EPMA and fluid inclusion data generated from the area indicate association of typical hydrothermal environment minerals like, Perkrite, Wittchenite, Aguilarite, Molybdnite etc. The mineralizing fluids have been trapped between the temperature ranges of 130°C to 375°C with average being 250°C to 300°C. The fluid salinity also varies from near pure hot water to moderately saline fluid indicative of multi-episodic mineralization of syngenetic nature coupled with epigenetic component. The ore textures indicate 500°C temperature range; certain intergrowths of minerals like specular hematite and bornite suggest the occurrence of hypogene environment induced due to emplacement of granite/pegmatite on the eastern and southern margins of the belt. The strata bound nature suggests the euxogenic environment facilitated by carbonate facies of rocks. The parallelism of sulphide with the rock fabric was attained during first deformation and the epigenetic component coupled with the hypogene assemblage was deposited during the D2 deformation in the brittle ductile shear zones and limb shears, between the temperature ranges of 130°C to 570°C as deduced from petrochemical data. Hence a comprehensive model is suggested here on evolution of process of mineralization in the Neem Ka Thana belt.

OCCURRENCE OF METFORMIN IN ENVIRONMENTAL WATER SAMPLES AND COMPARISON WITH CONSUMPTION DATA FROM A SURROUNDING HOSPITAL OVER 5 YEARS: A RETROSPECTIVE CASE STUDY.

The environmental occurrence of metformin has been frequently world-widely reported. Despite the diabetes susceptibility in the Chinese population, the studies on occurrence of metformin as environment disruptor in China are insufficient. To determine the occurrence trends and possible environmental pollution sources of metformin as an emerging micropollutant. High-performance liquid chromatography-electrospray ionization-tandem mass spectrometry system was used to detect the metformin levels in water samples collected from the Xi'an city Moat, China once a year from 2017 to 2021. Correlations among the metformin levels in moat water, in surrounding hospital wastewater, and hospital metformin consumption data were assessed using Pearson, Spearman and Kendall's tau-b correlation coefficients. Occurrence of metformin was found in Xi'an city Moat water with levels in the range of 304-793 ng/L. Significant correlations were found between the metformin levels in city moat water and the total (or outpatient) metformin utilization data of the hospital. Data suggested the potential environmental issues posed by metformin in Xi'an city in China. The metformin consumption volume in the surrounding hospitals, especially at the outpatient services, could be used to predict the metformin concentrations in the moat water.

Emerging Contaminants in Sediments as Markers of Anthropogenic Inputs in Santos Estuarine System: Analytical Method and Occurrence Data

The occurrence of emerging contaminants (ECs) in the aquatic systems under influence of urban areas have been considered as an environmental marker of anthropogenic contamination. In this study 10 ECs were investigated in sediment samples from Santos Bay using a quick, easy, cheap, effective, rugged, and safe method with determination by liquid chromatography tandem mass spectrometry. The method showed acceptable accuracy (51-116%) and precision (relative standard deviation (RSD) ≤ 9), limits of quantification in ng g-1 levels and matrix effect lower than 29%. Environmental occurrence of benzophenone-3, caffeine, ketoconazole and triclocarban was detected in two campaigns (2015 and 2019), with concentrations ranging from < 1 to 470 ng g-1. Caffeine and triclocarban were the most abundant target chemicals occurring in up to 71 and 100% of the sample point, respectively. The results indicated that ECs in sediment samples came from diffused sources as the discharge of treated and untreated sewage in the estuary.

Arsenic Occurrence and Cycling in the Aquatic Environment: A Comparison between Freshwater and Seawater

Owing to the toxicity and adverse effects of arsenic on human health, its levels in aquatic environments are among the most serious threats to humans globally. To improve our understanding of its occurrence and cycling in aquatic environments, herein we review the concentration, speciation, and distribution of arsenic in freshwater, seawater, and sediments. Many natural processes, such as rock weathering and geothermal activities, contribute to the background arsenic concentrations in the natural environment, whereas metal mining and smelting are anthropogenic sources of arsenic in the water. The high solubility and mobility of arsenic in aquatic environments affects its global cycling. Furthermore, the biological processes in the aquatic environment are discussed, especially the possible microbe-mediated reactions of arsenic in sediments. In addition, various environmental factors, such as redox conditions, pH, and salinity, which influence the transformation of arsenic species, are summarized. Finally, the differences between freshwater and seawater with reference to the concentration as well as speciation and distribution patterns of arsenic are addressed. This review provides deep insights into arsenic occurrence and cycling between freshwater and seawater aquatic environments, which can more accurately distinguish the risks of arsenic in different water environments, and provides theoretical guidance for the prevention and control of arsenic risks.

Potential Phytoremediation of Aquatic Macrophyte Species for Heavy Metals in Urban Environments in the Southern Area of Brazil

This research investigated four different species of aquatic macrophytes with natural occurrence in an urban environment highly anthropized in Southern Brazil. The aim of the research was to compare the phytoremediation potential among the species E. anagallis, H. grumosa, H. ranunculoides, and S. montevidensis through Pearson´s correlation analysis and cluster analysis, using the heavy metal content identified through HNO3 - HClO4 and phytoremediation indexes. The results highlighted the bioconcentration factor (BCF) of H. ranunculoides, with outstanding results for Cu BCF = 667.09, Zn BCF = 149.93, Cd BCF = 26.85, Cr BCF = 31.77, Ni BCF = 35.47, and Pb BCF= 126.29. Additionally, H. grumosa and S. montevidensis were also highlighted, considering the potential phytoremoval (g ha−1). Therefore, this study demonstrates the tolerance and potential for removal of heavy metals Cu, Cr, Cd, Pb, Ni, and Zn by the evaluated aquatic macrophyte species and elucidates the outstanding potential of application in phytoremediation purposes.

Analytical key issues and challenges in the LC-MS/MS determination of antibiotics in wastewater

The research on antibiotics occurrence in the aquatic environment has become a hot topic in the last years due to their potential negative effects, associated to possible bacterial antibiotic-resistance, after continuous exposure to these compounds. Most of antibiotic residues are not completely removed in the wastewater treatment plants (WWTPs) and end up in the aquatic environment through treated wastewater (WW). The development of reliable analytical methodologies for the determination of antibiotics in influent (IWW) and effluent wastewater (EWW) is needed with different purposes, among others: monitoring their occurrence in the aquatic environment, performing environmental risk assessment, estimating removal efficiencies of WWTPs, or estimating the consumption of these compounds. In this paper, we perform an in-depth investigation on analytical key issues that pose difficulties in the determination of antibiotics in complex matrices, such as WW, and we identify challenges to be properly addressed for successful analysis. The analytical technique selected was liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS), as it is the most powerful and widely applied at present for antibiotic residues determination. The mass spectrometric behavior of 18 selected antibiotics, the chromatographic performance, ion ratio variations associated to the sample matrix when using different precursor ions or protomers, and the macrolides adsorption to glass vial, were some of the issues studied in this work. On the basis of the detailed study performed, an analytical LC-MS/MS method based on sample direct injection has been developed for quantification of 18 antibiotics in IWW and EWW, allowing their determination at low ng L−1 levels.

A synthesis of the biogeographical distribution of Rotifera in Africa

Abstract The rotifer fauna of Africa has been studied for >100 years, but there has been no recent synthesis. We compiled data from 265 publications that reported information on African rotifers. Our dataset yielded information on the distribution of 765 taxa from ~1850 separate sites; these included both natural and artificial habitats such as lakes, ponds, puddles, oases, artificial systems, rivers and wetlands. A heat map of predicted rotifer biodiversity indicated that the greatest diversity should be present in the sub-Saharan region including a large hotspot in Mali and several smaller ones scattered in that region. Lakes Kariba, Tanganyika and Malawi showed high-predicted diversity, but surprisingly, Lake Victoria had lower diversity than expected. Two regions showed unusually high-predicted diversity: northwestern Algeria extending into Morocco and Egypt. Equatorial Africa is rich in habitats well suited for rotifers, yet their predicted biodiversity seems low. Latitude and elevation were negatively correlated with richness, while permanent water source and littoral zone were positively correlated according to generalized linear modeling results. Partial RDA analyses showed significant correlations among several environmental features and species occurrences. It is clear that more survey work remains to be done to achieve a better understanding of African rotifers.

Exposure to nitrogenous based flame retardants in Chinese population: Evidence from a national-scale study

Extensive use of nitrogen-based flame retardants (NFRs) has resulted in their widespread environmental occurrence. To investigate human exposure to NFRs on a national scale, the abundance and spatial distribution of NFRs were assessed in urine specimens collected from 13 cities in China. Six out of eight target NFRs were detectable in more than half of the urine samples, and the total concentrations of NFRs ranged from 3.22 to 880 ng/mL with a median of 46.7 ng/mL. Cyanuric acid was the most abundant chemical, accounting for 66.2%, followed by melamine (16.3%), ammelide (10.8%), and ammeline (6.11%). Regional differences in concentrations and composition profiles of NFRs were observed within China as a result of different production and application profiles. In addition, we found that urinary NFRs levels were much higher than but statistically correlated with that of organophosphates (r2 = 0.69, p < 0.05), another class of phosphorus-based flame retardant, implying similar emission sources and/or human exposure pathways. Furthermore, the estimated daily intakes and hazard quotients revealed that the Chinese population's exposure to NFRs is within safe limits. To the best of our knowledge, this is the first study to document the ubiquitous occurrence and region-specific variations of human exposure to NFRs in China.

Radiation-induced degradation of doxazosin: Role of reactive species, toxicity, mineralization and degradation pathways

State-of-the-art technologies based on advanced oxidation processes (AOPs) are currently being developed for the removal of environmental pollutants such as pharmaceuticals from water matrices. Such studies are very important and should include the impact of inorganic and organic matrix on the degradation process of pollutants. One of the AOPs that is in focus of investigations nowadays, is ionizing radiation. Doxazosin (DOX) is a widely used pharmaceutical for the treatment of hypertension, which can be potentially harmful due to its occurrence in the aquatic environment. This study reports the radiation-induced degradation of DOX in aqueous solution. Removal of 10 mg L−1 DOX reached almost 100 % at irradiation doses of 200 Gy regardless of the dose rate used. The effect of saturated solutions with N2, N2O, air and the addition of radical scavengers such as 2-PrOH and thiourea on DOX degradation was investigated. The efficiency of degradation increased in the order: thiourea < 2-PrOH < N2 < air < N2O. The effects of pH, various inorganic ions and water matrix on DOX degradation were also studied. DOX degradation was lower in underground water than in ultrapure water. Under prolonged irradiation, mineralization of about 60 % of DOX solutions was observed based on the dissolved organic carbon (DOC) evaluation. Toxicity tests with V. fischeri luminescent bacteria showed higher toxicity of samples irradiated at 500 Gy. The main degradation products were identified using LC-HRMS and degradation pathways were proposed. Overall, irradiation technology could be a promising technique for the removal of micropollutants, such as pharmaceuticals in real water matrices.

Bioaccumulation and Biotransformation of Chlorinated Paraffins.

Chlorinated paraffins (CPs), a class of persistent, toxic, and bioaccumulated compounds, have received increasing attention for their environmental occurrence and ecological and human health risks worldwide in the past decades. Understanding the environmental behavior and fate of CPs faces a huge challenge owing to the extremely complex CP congeners. Consequently, the aims of the present study are to summarize and integrate the bioaccumulation and biotransformation of CPs, including the occurrence of CPs in biota, tissue distribution, biomagnification, and trophic transfer, and biotransformation of CPs in plants, invertebrates, and vertebrates in detail. Biota samples collected in China showed higher CP concentrations than other regions, which is consistent with their huge production and usage. The lipid content is the major factor that determines the physical burden of CPs in tissues or organs. Regarding the bioaccumulation of CPs and their influence factors, inconsistent results were obtained. Biotransformation is an important reason for this variable. Some CP congeners are readily biodegradable in plants, animals, and microorganisms. Hydroxylation, dechlorination, chlorine rearrangement, and carbon chain decomposition are potential biotransformation pathways for the CP congeners. Knowledge of the influence of chain length, chlorination degree, constitution, and stereochemistry on the tissue distribution, bioaccumulation, and biotransformation is still scarce.